Drawing a clean polyline on the map - ios

Question

I'm working on iOS app that draw polyline on the map to highlight the route user has taken. I can draw the poly line with no problem. But, the line is not a clean line that you see on Googlemap. It's a bit squiggly like handdrawn as you can see in the pic. Apology for big images as I don't know how to resize them in SO.
How can I acheive the result like this one in the picture :
This is my code that is responsible for drawing poly line :
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
if let location = manager.location {
if (firstLoad) {
firstLoad = false
recentCoordinate = location.coordinate
mapView.camera = GMSCameraPosition(target: location.coordinate, zoom: Constants.MapView.Zoom, bearing: 0, viewingAngle: Constants.MapView.ViewingAngle)
}
else {
mapView.animateToLocation(CLLocationCoordinate2D(latitude: location.coordinate.latitude,longitude: location.coordinate.longitude))
}
// this is suppose to filter out noise. I don't think it's working
let age = 0 - location.timestamp.timeIntervalSinceNow
if (age > 120) {
return; // ignore old (cached) updates
}
if (location.horizontalAccuracy < 0) {
return; // ignore invalid updates
}
if (location.horizontalAccuracy <= 10){
// this is a valid update
// Draw route as user moves along
path.addCoordinate(CLLocationCoordinate2D(latitude: location.coordinate.latitude,
longitude: location.coordinate.longitude))
let polyline = GMSPolyline(path: path)
polyline.strokeColor = UIColor.redColor()
polyline.strokeWidth = 3
polyline.map = mapView
// Save the coordinates to array
coordinateArray.append([location.coordinate.latitude, location.coordinate.longitude])
}
}
}